Speed-change gearing



Feb. 17, 1942. R. WOYTY CH SPEED-CHANGE GEARING" Original, Filed June 7,1939 2 Sheets-Sheet 2 Patented Feb. 17, 1942 SPEED-CHAN GE GEARINGRaymond M. Woytych, Fond du Lac, Wis., as-

signor to Giddings & Lewis Machine. Tool 00., Fond du Lac, Wis., a.corporation of Wisconsin Original application June 7, 1939, Serial No.277,757. Divided and this application April 15, 1940, Serial No. 329,699

3 Claims.

The invention relates to improvements in speed-change gearings. Thepresent application is a division of my copending application Serial No.277,757, filed June 7, 1939, Patent No. 2,269,- 641 issued January 13,1942. In said copending application is described and claimed a facingattachment for horizontal boring, drilling and milling machines, thepresent speed-change gearing being particularly-adapted for use in sucha machine tool attachment although it will be plain to those skilled inthe art that speed-change gearings embodying the present invention mayalso be desirably used in a wide variety of other types ofinstallations.

One object of the present invention is to provide a speed-change gearingof novel form such that gears of small diameter serve to accomplish awide range of speed adjustment.

A more specific object is to provide a speedchange gearing and aplurality of selectively available gear connections which hear anadditive, and preferably true geometric-progression relation to eachother.

Another object is to provide a speed-change gearing which is extremelycompact and low taken respectively along the lines 2-2 and 3-3 of Fig.1.

Fig. 4 is a generally diagrammatic layout or development of the gearing.

Fig. 5 is an end elevation, partially in section, of the automaticreversing mechanism associated with the speed-change gearing.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawings and will hereindescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific formdisclosed, but intend to cover all modifications and alternativeconstructions falling within the spirit metric-progression relation tothe other settings.

In this way a gearing of small over-all dimensions is achieved suitablefor housing within a confined space such, for example, as in a machinetool attachment head. The gearing herein shown is capable of sixdifferent speed settings, although it will be clear to those skilled inthe art that a greater or lesser number may be provided as desiredwithout departing from the disclosed plan or construction.

The speed-change gearing shown is interposedbetween a power inlet ordriven shaft "I (Fig. 2) and a power take-off or outlet shaft 23, adrivekey shaft ll being axially slidable in the latter. The drive shaftI is, in the present instance, a stub shaft journaled in a suitableframework I2, and having fixed on its outer end a spiral gear l3, whichis in turn driven by a meshing spiral gear l4. On the inner end of theshaft I4 is a first driving gear cluster including a gear l and a pinionl6. Coaxial with this gear cluster is a stationary shaft I'l also havingloosely journaled thereon two further gear clusters each made up of oneof the pinions l8 and I9, and a corresponding one of the gears and 2|.Further, the speed-change gearing includes a stationary intermediateshaft 22 (Figs. 1 and 3). On this intermediate shaft 22 are looselyjournaled a gear 24 and two gear clusters made up respectively of gears25 and 26, as well as pinions 21 and 28. On the shaft 23 sixdriven gears29-34 are loosely journaled, which correspond to the six different speedsettings of the speedchange gearing. To condition the gearing for aselected speed setting, the corresponding one of the driven gears isconnected to the driven shaft 23 by a drive key (Figs. 1 and 2). Thisdrive key is of conventional form being yieldably urged into' engagementwith a registering one of the gears by springs 36. Pin 31 holds thedrive key in .position on the shaft II and the nose of the drive keyprojects through a slot 38 in the side wall of the tubular driven shaft23 into engagement with a slot in.the hub of the registering one of thedriven gears (Fig. 1).

To shift the drive key 35 axially of the tubular shaft 23 intoengagement with a selected one cf the driven gears 29-34, a manuallyoperable speed selection mechanism is provided. This mechanism includesa stub shaft 39 (Figs. 3 and suitably journaled in the framework l2 andhaving a squared recessed end to receive a hand crank (not shown). Adial 40 indicates the speed setting. Fast on the stub shaft 39 is apinion 4| meshing with a circular toothed rack 42 on the free end of theshaft H so that rotation of the pinion 41 serves to shift the shaft llaxially and to bring the drive key 35 into engagement with the desiredone of the driven gears.

The various trains of gears which are active for the different speedsettings can best be seen by reference to the diagrammatic layout inFig'l 4. In this layout or development of the gearing the series ofdriven gears have been reproduced at both the top and bottom of thefigure. In the event that the drive key 35 engages, for example, thedriven gear 29 (as shown in full lines in Fig. 4) the drive is directlyfrom the driving gear l5 to the meshing driven gear 29. Similarly, whenthe drive key 35 is shifted into engagement with the next driven gear 30the drive is from the drive pinion l6 to the meshing intermediate gear26 and thence to the driven gear 30. The table below sets out the gearconnections for the six different settings of the speed-change gearing.

From an inspection .of the foregoing tabulation it will be seen that thevarious driven gears are meshed into the series train of cluster gearsat successive points. In this way all of the gears used in the secondsetting are used in the third, all of those in the third are used in thefourth, etc. so that a minimum number of gears are required for maximumvariations in speed.

In the illustrative construction all of the driven gears 29-34 aresubstantially identical and all have pitch circles the same as those ofthe gear 20 and the gears in the various clusters. Though the pinionsare of the same diametrical pitch as the gears they may have anyparticular desired ratio of tooth number to that of the correspondinggears depending upon the speed reduction desired. By way of example, thepinions may all have eighteen teeth and the gears all thirtythree teeth.In such case the ratios of speeds for the six different settings of thegearing constitute a geometric progression, which is an especiallydesirable relation since from such a series may be quickly and easilyselected a suitable drive speed for, say, amachine tool element.

The speed-change gearing described above is such that the direction ofrotation of the driven shaft 23 is reversedfor alternate settings of thespeed-change gearing. It is desirable, however, that a final powertake-off shaft 43 (Fig. 5)

which the shaft 23 drives, as described below, be

driven unidireetionally despite changes in speed as previously notedand, accordingly, a reversing clutch 44 is arranged to be automaticallyactuated in accordance with the setting of the speedchange gearing so asto compensate for the reversals in the speed-change "gearing. Toestablish a driving connection between the driven shaft 23 and theoutlet shaft 43, the former is connected by bevel gears 56, 51 with arotatably journaled shaft 5|. Loosely journaled on the lower portion ofthis shaft 5| are opposed bevel gears 58, 59 having fast on them,respectively, toothed clutch elements 52, 53 of the reversing clutch 44.The outlet shaft 43 has fixed on it a bevel gear 62 meshing with thebevels 58, 59. Accordingly, the reversing clutch 44 connects theintermediate shaft 5! to the outlet shaft 43 by alternatively connectingone or the other of the bevel gears 58, 59 to the shaft 5|.

As a means of actuating the clutch 44 in response to changes in settingof the speed-change gearing a three lobe peripheral cam 45 (Figs. 3 and5) is fixed on the setting-control shaft 39 of the speed-change gearing.An axially slidable cam follower rod 46 is urged against the cam 45 by acompression spring 4! bearing against a collar 48 pressed against ashoulder on the rod (Fig. 5). A clutch shifter shoe 49 slidably carriedon the rod 46 serves to shift a toothed clutch driver 50 which issplined on the shaft 5|, into engagement with one or the other of thetoothed driven clutch members 52, 53. The cam 45 is indexed a sixth of arevolution for each step in the gear setting so it alternately brings alobe and a depression into engagement with the cam follower rod 46 withthe result that the upper and lower clutch members 52, 53 arealternately engaged. I

To avoid jamming and breakage of the clutch by positive actuation of itby the cam 45 when the clutch teeth are not in registry, a yieldableconnection is used between the cam follower rod 46 and shifter shoe 49.For this purpose a second compression spring 54 is interposed betweenthe shifter shoe and a collar 55 pinned 0n the rod. With thisarrangement when the rod 46 is pushed downward (as viewed in Fig. 5) bythe cam 45, the thrust transmitted from the rod 46 through collar 55 andspring 54 compresses the lower spring 41, thereby permitting the shiftershoe 49 to move down and engage the clutch driver 50 with the lowerclutch member 53. In the event that the teeth on clutch parts 53 and 53are not in registry at the instant the rod 46 descends, however, thespring 54 is also compressed to store up the thrust force and thereafterexpands to push the shifter shoe 49 down as soon as the teeth doregister on further rotation of the shaft 5|. Similarly, when the upperend of the rod 46 rides into a low point on the cam 45 the spring 41 isreleased to thrust the rod 46 and shifter shoe 49 upward. Since thisupward thrust is applied by a yieldable spring, however, final upwardmovement of the clutch driver 50 to engage the driven member 52 does nottake the reversing clutch automatically retains the rotation of theshaft 43 unidirectional.

In view of the foregoing it will be apparent that I have provided ahighly effectual and eflicient speed-change gearing of extremely compactform. In addition to the small over-all dimensions of the gear used,despite the wide changes in speed ratios achieved, many of the gearelements are substantially duplicates so that manufacturing cost is alsominimized.

I claim as my invention:

1. The combination of a gear train embodying a plurality of gearsarranged in series relation and adapted to be driven in series from oneterv mine! of the train, a plurality of freely and independentlyrotatable driven gears arranged with each one meshing with a differentgear in said train, part of said driven gears being rotated in theopposite direction with respect to the remainder, a driven member,selector means for connecting any selected one of said driven gears indriving relation with said driven member, a rotatable power take-ofidevice, means including a reversing clutch for connecting said drivenmember in driving relation with said power take-oil device, and meansfor actuating said reversing clutch as an incident to the operation ofsaid selector means for maintaining unidirectional rotation of saidpower take-oil device irrespective of the direction of rotation of theselected driven gear.

2. In a speed-change gearing, the combination of a plurality ofdual-unit gear clusters, each embodying a pinion and a gear fixedtogether and arranged coaxially, said gear clusters being arranged inseries relation in a train with the pinion of each cluster meshing withthe gear of the next cluster in the series, means for driving the trainof clusters from one of the terminal clusters of the train, a pluralityof independent- 1y rotatable driven gears each meshing with a diil'erentone of the cluster gears, whereby alternate ones of said driven gearsare rotated in opposite directions with respect to each other, a drivenmember, selector means for connecting any selected one of said drivengears in driving relation with said driven member, a rotatable powertake-oil device, means including a reversing clutch for connecting saiddriven member in driving relation with said power take-off device, andmeans for actuating said reversing clutch as an incident to theoperation of said selector means for maintaining unidirectional rotationof said power take-oil device irrespective of the direction of rotationof the selected driven gear.

3. In a speed-change gearing, the combination of two sets of gearclusters arranged with the clusters in each set coaxial and with theaxes of the two sets parallel, each of said clusters embodying a pinionand a gear coaxially arranged and fixed together, said clusters in bothof said sets being arranged to mesh in a single series train with thepinion of each cluster in one set meshing with the corresponding gear inthe other set of clusters, a plurality of independently rotatable drivengears each meshing with a dif ferent one of the cluster gears, a drivenshaft, means journaling all of said driven gears for independentrotation about the axis of said driven shaft, means including adrive-key for connecting any selected one of said driven gears to saiddriven shaft, a rotatable power take-off device, means including areversing clutch for connecting said driven shaft in driving relationwith said power take-off device, and means for actuating said reversingclutch'as an incident to a change in setting of said drive-key formaintaining unidirectional rotation of said power takeoff deviceirrespective of the setting of said drive-key.

RAYMOND M. WOYTYCH.

